This report is one of a series issued in cooperation with the Army-Navy-Civil Committee on Aircraft Design Criteria under the supervision of the Aeronautical Board.
Aerial surveys of six Montana National Forests in 1975 found a 22.1% increase in the area of visible defoliation caused by the western spruce budworm. It is estimated that 2,278,804 acres of Douglas-fir forests are now suffering at least 25% defoliation. This is an increase of 503,706 acres over the...
A pilot project to evaluate trichlorfon and acephate for suppressing western spruce budworm populations was conducted on the Helena National Forest, Montana. Both insecticides were applied at 1 pound active ingredient per acre. Application was made with a Bell 205A helicopter using eight Beecomist Model 350 spray heads. Treatments and...
Published November 1956. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog